To determine the mechanism of catalysis of renaturation by T4 phage gene 32 product and similar proteins. This work should also help to integrate renaturation kinetics data with cyclization kinetics data for bacteriophage DNAs with complementary single stranded ends. To determine whether the distribution of the ends of denatured and renatured circularly permuted, terminally redundant DNA is the result of a physical (excluded volume) or biological (the mechanism of DNA replication). To develop a model system relating sequence repetition organization to renaturation kinetics. To develop methods of labeling nucleic acids prior to hybridization so that hybrids may be physically separated for subsequent electron microscope studies. To develop quantitative analytical methods for handling nanogram quantities of hybrid molecules for subsequent electron microscope studies.